Daylight loading developing tank



Aug. 28, 1951 c. F. ZOBEL 2,556,281

DAYLIGHT LOADING DEVELOPING TANK Filed Nov. 15, 1947 FIG. 3.

FIG.4.

CARL F. ZOBEL INVENTOR ATTORNEYS the spool.

Patented Aug. 28, 1951 DAYLIGHT LOADING DEVELOPING TANK Carl F. Zobel, Rochester, N. Y., assignor to Eastman Kodak Company, Rochester, N. Y., a corporation of New Jersey Application November 13, 1947, Serial No. 785,709

2 Claims.

The present invention relates to a processing device for photographic film and more particularly to a daylight-loading developing tank especially adapted for roll film and for amateur use.

Many varieties of this type of developing tank are in extensive use by amateur photographers who process their own film. These devices have been subject to numerous criticisms. For one thing, in devices in which the film is wound upon a take-up spool in the tank the film often hecomes disengaged from the spool which necessitates opening of the tank before the processing has been completed to again secure the film to To avoid such a possibility, numerous means have been devised for fastening the film to the core of the film spool. These have often been needlessly complex and not always a satisfactory solution. Again, in developing devices in which a strip film is wound back and forth between a supply spool and a take-up spool, no eliective simple method has been devised whereby the tension on the film strip can be so controlled that the danger of tearing the film from the supply spool or from the take-up spool can be substantially eliminated. When the film is so torn, the tank must be removed to the dark room, opened and the break repaired, this, of course, defeating one of the primary advantages claimed for this type of developing device.

My invention is intended to remedy the above faults. In addition, my device is particularly well adapted for the developing of roll film which is wound upon a spool having film-retaining shoulders on the spool flanges as will be apparent from the following description.

It is, therefore, an object of this invention to provide an improved processing device for roll film.

It is a further object of this invention to provide an improved daylight-loading developing tank for roll film in which the film is wound back and forth between two film spools immersed in a processing fluid.

It is a still further object of this invention to provide a daylight-loading developing tank of the character described in which improved winding means restrict the degree of tension which may be inadvertently applied to the film to substantially preclude tearing of the film from the spool.

It is a still further object of this invention to provide an effective means for securing the end of a strip film to a film spool.

It is a Still further object of this invention to provide an amateur developing tank of the character described which is particularly adapted for the development of roll film which is wound upon spools having film-retaining shoulders 'on the spool flanges.

It is a still further object of this invention to provide a daylight-loading developing tank which is simple in construction, relatively inexpensive,

Other objects and advantages of the invention will become apparent from the following description taken in connection with the accompanying drawing, and it will be understood that many changes may be made in the details of construction and arrangement of parts shown and described without departing from the spirit of the invention as'expressed in the accompanying claims. I, therefore, do not wish to be limited to the exact details shown and described as the preferred form only has been shown by way of illustration.

In the drawing:

Fig. 1 is a'plan view of a daylight-loading developing tank embodying the present invention;

Fig. 2 is a sectional elevation taken on the line 2-2 of Fig. 1;

Fig. 3 is an end view of the take-up spool illustrating the means bywhich the film isfastened to the spool core; and

Fig. 4 is a section through the light-tight entrance into the tank taken on line 4-4. of Fig. l.

The'daylight-loading developing tank embody ing this invention includes the tank ill and the cover H which has a light-tight fit with the tank to exclude light. Two spindles I2 and it are journalled in the openings [8 and IS in the cover to support the film spools in the tank. The spindles are secured to the cover by means of the discs [4 and I5 integrally formed therewith and the spring washers l6 and ll. The discs Hi and I5 also serve to make the openings l8 and light-tight. The spring washers it and. H fit securely upon the spindles l2 and i3, respectively, having a friction fit therewith. A more positive grip can be effected by providing one or more small protuberances upon the spindles over which the washers may be forced. In addition to serving as retaining means the washers and I! function to retard rotation of the spindles. Such resistance to rotation is desirable to prevent the resilience of the film itself rotating the spindles. The spring washers l6 and ll are each provided with several resilient fingers 2! wh ch are in frictional engagement with the cover H and spindles. It is apparent, however, that there are other known types of spring washers which may be employed to serve the desired end.

The tank I is provided with a well 2I through which a processing fluid may be admitted to the closed tank without breaking the light seal. This fluid enters the main body of the tank from the well by passing between a series of light baffles as will be understood from Fig. 1. Two of such baflles 22 and 23 depend from the cover II and are received in the slots 24 in the base of the tank I0, as may be seen in Fig. 4. Two other bafiles 25 and 26 are integral with the tank extending from adjacent walls thereof to outline the well 2|. These baflies fit in slots 21 in the cover and are positioned between the baffles 22 and 23 to form the light-tight passage from the well to the tank proper as seen in Fig. 1.

Spindle I2 is provided at one end with a threaded portion 28 upon which may be threaded the nut 29 by means of which a film spool 3| may be secured upon the spindle I2. The nut 29 has a broad base 36, the purpose of which will be later apparent. Spindl I3 has integral therewith the film take-up reel or spool 32 which includes the flanges 33 and the hollow core or hub 34. The core or hub 34 has a longitudinal slot 35 which is adapted to receive the end of the film strip 39. The film is locked in the core by the wire element 36. The latter, formed of resilient material, has a U-shaped portion 31 which is adapted to be inserted endwise into the hollow hub, the legs of the U bearing resiliently against the inner wall thereof. One of said legs is extended and bent to form a crank handle 38 to facilitate rotating th wire element 33. To fasten the film 39 to the take-up spool 32 the film end is inserted in the slot 35 and the handle 38 turned clockwise to approximately the position indicated by broken lines in Fig. 3. In this position one of the legs of the U-sh-aped portion will have resiliently pressed the film end against the inner wall of the hollow core whereby the film will be secured to the take-up spool.

A detachable handle 46 is provided which is adapted to be readily attached to either of the spindles I2 or I3. The handle includes the knob 4 I having a bore therein and a flexible crank arm 42 which extends through the bore. Each spindle .has a slotted end which fits snugly into the bore of the knob, the extension of the crank arm in the bore fitting within the slot in the spindle :end. This permits the knob to positively drive the spindle and still be readily detachable therefrom. The flexible crank arm 42 is formed of a :resilient material and functions to limit the :amount of torque which may be unwittingly applied to the spindle, thereby substantially eliminating the possibility of tearing the film from either film spool by overwinding.

Certain films are provided with a jet backing which takes the place of the paper backing commonly used. Since this backing must be removed in processing the film, I provide a buffer roller 43 which is preferably rotatably mounted on the cover II and suspended in the tank Ill. The buffer is preferably covered with mohair. A spring washer may be used on the buffer shaft to restrict the rotation of the roller whereby the back of the film in being pulled over this roller is efiectively scrubbed to remove the said backmg.

The developing tank described above is particularly adapted for the processing of roll film which is wound upon spools having film-retaining shoulders on the spool flanges. Such a spool 3| is illustrated mounted on the spindle I2 in Fig. 2, the shoulders 44 serving to retain the film on the spool. In operation, the spool 3| is first placed upon the spindle I2 and locked thereon by means of the nut 29. By slightly bowing the film end a short length is pulled ofi the spool and passed around the bufier roller (as shown by the lower broken line in Fig. 1) and fastened to the take-up reel or spool 32, as described above. The cover I I is now placed upon the tank It, the detachable handle is placed on spindle I3, and the film wound upon the spool 32 by rotating the handle clockwise until resistance to turning occurs.

As stated above, the crank arm 42 will provide sufiicient flexibility to prevent the film from being torn from the supply spool 3 I.

Developing solution is poured into the well 2| until a level is reached which will be sufiicient to cover the film in the tank. The handle 40 is removed from spindle I3 and placed upon spindle I2 and the crank turned counterclockwise. The film in being wound back upon spool 3| will be wound upon the shoulders 44 (as shown by the upper broken line in Fig. 1) rather than upon the core of the spool. Because of this, and to allow for looseness in rewinding the film during processing, the base 30 of the nut 29 and the disc I4 are larger than the supply spool flanges. The film and solution are agitated by winding the film back and forth between the spools. The solution itself serves to lubricate the film. After the developing has been completed, the solution is poured off without removing the tank cover. The film is then rinsed by repeating the above operation, the tank having first been filled with water. After the rinse water is poured off, the tank is filled with a fixing bath and the film is again wound back and forth until the processing has been completed. A final washing may be .performed in the tank itself, although this last operation may be effected after the film has been removed from the tank. In any event, after the last operation has been completed in the tank, the film is rewound upon spool 3|, the tank opened and the film end detached from spool 32, the former being removed from spindle I2 by unscrewing the nut 29.

The various components of the above-described developing tank may be constructed of stainless steel, plastic or an material that is not affected by th chemicals employed in the various processing operations.

From the foregoing description, it will be apparent that I have provided means for obtaining tall the objects and advantages of this invenion.

What I claim and desire to secure by Letters Patent of the United States is:

1. A daylight-loading processing tank for roll or strip film comprising a tank, a light-tight cover for said tank, a spindle journalled in and secured to said cover, means on said spindle for locking a film spool thereon, a, second spindle journalled in and secured to said cover, a film spool comprising a slotted, hollow hub on the secondspindle and rotatable therewith, rotatable, resilient means insertable endwise into said hub and adapted, when rotated, to resiliently press the end of the film strip which has been passed through the slot into the hollow hub against the inner wall thereof, whereby the film is fastened to said second film spool, a single handle secured to one of said spindles and being adapted to be readily detached therefrom and detachably secured to the other spindle, the handle including a flexible, resilient crank arm whereby tearing of the film from a. film spool by overwinding will be substantially eliminated, and a light-tight opening for admitting fluid to said tank.

2. A daylight-loading processing tank for roll or strip film comprising a tank, a light-tight cover for said tank, a pair of spindles journalled in said cover, a, spring washer on each spindle adapted to secure the latter to the cover and to retard rotation of the spindle by the friction developed between the cover and the washer, means on one end of one of the spindles for locking a film spool thereon, a film spool comprising a slotted, hollow hub on the other of said spindles and rotatable therewith, rotatable, resilient means insertable endwise into said hub and adapted, when rotated, to resiliently press the end of the film strip which has been passed through the slot into the hollow hub against the inner wall thereof, whereby the film is fastened to said second film spool, a bufier roller mounted on said cover to project into the tank and positioned to scrub the back of the film as it is wound between the two film spools, a single handle secured to one of said spindles and being adapted to be readily detached therefrom and detachably secured to the other spindle, the handle including a flexible crank arm whereby tearing of the film from a film spool by overwinding will be substantially eliminated, and a light-tight opening for admitting fluid to said tank.

CARL F. ZOBEL.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 976,800 Hayden Nov. 22, 1910 1,013,882 Lasker Jan. 9, 1912 1,381,548 Halmer June 14, 1921 1,599,484 Penin Sept. 14, 1926 1,949,868 Keuifel Mar. 6, 1934 2,066,732 Kunz Jan. 5, 1937 FOREIGN PATENTS Number Country Date 275,349 Great Britain Aug. 11, 1927 

